The sarcoidosis population used in this study was recruited as part of the NHLBI funded Genomic Research in Alpha-1 Antitrypsin Deficiency and Sarcoidosis (GRADS) study. The GRADS study is a multi-center, observational cohort exploring the role of the microbiome and genome in subjects with alpha-1 antitrypsin deficiency and/or sarcoidosis [1]}. Subjects were eligible for GRADS if they were between the ages of 18 and 85 years, had a confirmed diagnosis of sarcoidosis via biopsy or manifestations consistent with acute sarcoidosis (Lofgren's syndrome), met one of the nine study phenotypes and provided signed informed consent [1]}. As part of GRADS, uniform clinical data was obtained including pulmonary function testing, a chest radiograph (for Scadding staging classification), and a research chest high resolution CT based on the COPDGene protocol [3]}. Research chest HRCTs used in this study were acquired under a variety of scanner manufacturers, with the participants in the supine position during breath holding at end inspiration, and the following parameters: 500 msec exposure time, standard B35f kernel, approximately 0.75 mm thickness, and computed interval of approximately 0.5 mm [4]}.
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